1. Field of the Invention
The present general inventive concept relates to a developing cartridge and an image forming apparatus having the same, and more particularly, to a developing cartridge having an improved supporting configuration of a supplying member to supply developer to a developing member and an image forming apparatus having the same.
2. Description of the Related Art
In general, an image forming apparatus forms an image signal received from a host apparatus on a printing medium as an image. For this purpose, a developing cartridge which stores developer is detachably mounted to the image forming apparatus. The developing cartridge comprises a photosensitive body to form an electrostatic latent image by a potential difference, a developing member to supply the developer to the electrostatic latent image, and a supplying member to supply developer to the developing member. The photosensitive body, the developing member and the supplying member are provided in a roller type to rotate facing each other, respectively.
In the image forming apparatus according to conventional technology, the supplying member rotates facing the developing member so that mutually facing areas therebetween can move in an opposite direction, and forms a nip of a predetermined interval therebetween. Accordingly, the supplying member supplies the developer onto a surface of the developing member, and resets a remaining electric potential of the developing member after supplying the developer onto the photosensitive body.
However, the conventional image forming apparatus has following problems. In general, the supplying member comprises urethane foam or silicon foam and stress on the developer is severely generated in an area forming a nip with the developing member. Due to the stress, an external additive of the developer drops out to result in a reversed polar developer, to thereby cause a background phenomenon or a ghost phenomenon, and to lower a reproducibility of a dot or a resolution of the image, and accordingly, an entire image quality formed on a printing medium is depreciated.
Meanwhile, so as to solve the problem, an image forming apparatus including a supplying member which is formed with a fur brush on its circumference has been proposed. Such image forming apparatus has an advantage to form a smaller nip between the developing member and the supplying member in comparison to where a supplying member in urethane foam or silicon foam is applied.
However, in the conventional image forming apparatus is deposited developer in the fur brush during the use, and the deposited developer is cured as long time passes after the driving of the apparatus. As a result, a layer of the cured developer suddenly increases torque in initial driving of the developing cartridge to cause a misalignment phenomenon, and at the same time, to cause the same problem where the supplying member in the urethane foam or the silicon foam is applied.